Thanks for the feedback!
Positioning is more about range control and blocking sightlines. Flanking matters only vs. walkers and tanks, but it could be more prominent (infantry and monsters do not care about that). It's a bit of a hidden mechanic, but if you charge with two units with more than a 45° angle between them, the enemy unit can't mount a counter-charge and get charge bonuses.
Militia is the cheapest unit and not very cost-effective at firepower, and its battleshock rule indeed makes it a strategic liability. Its point is that it is a dirt-cheap relay objective-contesting unit, and it has the Secure Ground rule, which lets it always take objectives unless opponents have the same rule. They're really effective as cannon fodder and for holding objectives. However, their discipline and skills are abysmal, if they ever get into melee, they may just keep falling back. But with the Vanguard faction, the Riflemen are much better infantry, and they can even get special weapons.
Feedback is valuable, that's how games get better!